The invention relates to an apparatus for manufacturing molded plastic articles or for manufacturing hollow foamed articles, comprising a closing unit with a first mold half and at least two further mold halves which are disposed on a support structure and are alternately movable either in the closing direction simultaneously with the first mold half or into the closed position above the first mold half.
German patent 3,110,303 discloses a process and an apparatus for manufacturing multilayer molded articles from at least two polyurethane systems, wherein at least two different upper mold halves are successively associated with a lower mold half to form the various layers. The two upper mold halves are disposed at an angle of 90.degree. on a support body which is rotatable about an axis inclined at an angle of 45.degree. to the horizontal. The axis is supported in a vertically displaceable holding device so that the upper mold half lying in working position may be lowered onto the lower mold half. After closure and injection of the first reaction mixture, the holding device of the axis is raised again and the form tool is opened. The support body is swivelled 180.degree. about the inclined axis so that the second upper mold half is positioned over the lower mold half. After closure of the form tool, the second reaction mixture is introduced. This type of changeover apparatus for the upper mold half is very expensive and, because of the inclined axis, the power usage is very high. The construction is also very difficult to access for maintenance work or for exchanging the upper mold halves. German Patent 2,724,929 describes a similar apparatus.
German Patent 3,530,831 discloses an apparatus for producing refrigerator cabinets. In the apparatus described, a transverse axis is disposed with clearance above a lower support mold half. A support body having a plurality of different upper support mold halves in the form of cores is supported and is rotatable about the axis. While the outer geometry of various refrigerator cabinets is frequently identical, the inner geometry generally varies. Thus, to change the inner geometry, the appropriate support core is used as an upper mold half while the support body is suitably rotated until the appropriate support core is positioned in the closing direction. This apparatus also has the drawback that the upper mold halves are difficult to access for maintenance work and for exchange operations.
The object of the present invention was the design of the above type of apparatuses in such a way that the alternately usable mold halves, as a result of being more accessible, are easier to maintain and exchange and in such a way as to require a smaller amount of floor space.